CentOS 7 系统下连续执行多条命令方法

CentOS7下多条命令可以放在一行上面执行，其执行情况得依赖于在命令之间的分隔符。

如果每条命令被一个分号 (;) 分隔，无论中间是否有错误的命令，命令会连续的执行下去，直到执行完毕，如：

[root@node1 ~]# printf "%s\n" "First command" ; date ; printf "%s\n" "Third command"

First command

Mon Oct 19 10:28:31 CST 2020

Third command

[root@node1 ~]# printf "%s\n" "First command" ; data ; printf "%s\n" "Third command"

First command

-bash: data: command not found

Third command

如果每条命令被 两个与号(&&)分隔，如果中间有错误的命令，则不再执行后面的命令，没错则执行完毕为止，如：

[root@node1 ~]# printf "%s\n" "First command" && date && printf "%s\n" "Third command"

First command

Mon Oct 19 10:27:56 CST 2020

Third command

[root@node1 ~]# printf "%s\n" "First command" && data && printf "%s\n" "Third command"

First command

-bash: data: command not found

如果每条命令双竖线(||)分隔，如果命令遇到可以成功执行的命令，那么命令停止执行，即使后面还有正确的命令而后面的所有命令都不到执行；假如命令一开始就执行失败，那么就会执行 || 后的下一条命令，直到遇到有可以成功执行的命令为止；假如所有命令的都失败，则所有这些失败的命令都会被尝试执行一次，如：

[root@node1 ~]# printf "%s\n" "First command" || date || printf "%s\n" "Third command"

First command

[root@node1 ~]# data || printf "%s\n" "Second command" || printf "%s\n" "Third command"

-bash: data: command not found

Second command

[root@node1 ~]# data || lll || lls

-bash: data: command not found

-bash: lll: command not found

-bash: lls: command not found

[root@node1 ~]# data || lll || lls || printf "%s\n" "Fourth command"

-bash: data: command not found

-bash: lll: command not found

-bash: lls: command not found

Fourth command